Breeding Better Corn On-Farm Frank Kutka Seed We Need & NPSAS
Maize can be nutritious and delicious!
Mean yields and grain quality for maize varieties evaluated at 71,000/ha in three organically managed fields in New York, 2002 Variety Yield % CP % Fat % Ash White Flint 1223 d 11.4 a 5.8 a 2.1 a Golden Glow 2032 d 11.2 a 4.9 bc 1.6 c Nokomis Gold 3687 b 10.5 b 5.0 b 1.6 c Wapsie Valley 3355 c 10.6 b 4.7 c 1.7 b Pio brand 35P12 6478 a 9.5 c 3.9 e 1.5 d Pio brand 36B08 6716 a 9.2 cd 4.0 e 1.5 de MC brand MC530 4321 b 8.9 d 4.5 d 1.4 e MC brand MC540 4007 b 9.1 cd 3.9 e 1.4 e
Maize brings to us the colors of the rainbow! Dave Christensen, Seedweneed.com
And it is incredibly adaptable!
The Old, Casual Way -All ears to a storage crib or bin in fall -Select nice looking, big ears in spring -Select ears for form -Shell just enough ears to plant -Plant by other corn
Focus on YIELD, but don t forget quality, dry down, etc.!
Remember these: P = G + E G x E
No G x E
G x E
G x E
DON T PANIC! This is what breeders can tell us about expected gain from selection: Kaσ A 2 + β Y [(σ W2 /krly)+(σ E2 /rly)+(σ GLY2 /ly)+(σ GY2 /y)+(σ GL2 /l)+σ A2 +σ D2 +σ I2 ] Remember what follows
Greater diversity often helps More intensive selection speeds gain Prevent inbreeding Increase heritability Reduce G x E Select in your target environment Pollen Control
Hybrid Corn: Can we save this?
How Heterosis Works Locus Genotype A B C D E Breed A A/A b/b C/C d/d e/e Breed B a/a B/B c/c D/D E/E A B (F 1 crossbred) A/a B/b C/c D/d E/e Table 1 from Olson, 1998
How do we get a diverse population that is worth growing and closer to our goals? Composites Synthetics F2 = F1 ((F1-P)/N) Wright s formula (1922)
What is a Diallel Cross? Motto Syzldecka Pervenets Rutherford A mix of varieties is a Composite
results indicate definitely also that synthetics may be expected to perform better than the open-pollinated variety from which they are selected and in some comparisons equal to or better than comparable double crosses [hybrids]. H.K. Hayes, 1963 A Professor s Story of Hybrid Corn
An example of a Synthetic : Pa91, B73, B84, B77 H100, Mo17, N152, B79 79% of best hybrid yield
Selection Intensity Best to keep 100+ ears to prevent inbreeding 100 best ears of 100 plants is NO SELECTION 100 best ears of 1000 plants is 10% 100 best ears of 10,000 plants is 1% Have to be THE BEST!
Selection Intensity From Fehr, W.R. 1991. Principles of Cultivar Development.
One Way to Control E: Gridded Mass Selection Harvest best 1-10% of ears as seed ears from small, gridded plots across the field Dry and store them in a cool, dry location. Take an equal number of seeds from each ear to replant next season. Don t worry about ear type. Focus on yield of dry seed from healthy, upright plants (kick, pull, leave standing) grown with some stress. Save seed from at least 100 plants from plots spread across the field and all of its soil types
-Pick seed ears from smaller plots (these have 80 plants that are all on similar soil) -Choose best plants in each grid, (4 plants means best 5% is selected) -Select at least 100 plants from many gridded plots across the entire field
What if we selected ears based on their offspring? Ear Rows
Modified Ear Row Selection
A More Intense Method: Modified Ear To Row Selection Choose best 200 or more ears from a population using gridded mass selection The following season randomly plant short rows of 20 seeds from each of these ears (ear rows). Plant out fields like this in three locations One field is the crossing field. Every fifth row in the field and the border rows are planted with bulk seed from all the parent ears In the crossing field detassel all of the plants in the ear rows, but do not detassel the plants in the bulk rows (these are the males)
A more intense method: Modified Ear To Row Selection Pick and bag by row all the ears from each of the ear rows. Make sure to mark the ten best ears in each row from the crossing field Weigh and moisture test all the ears from the ear rows in bulk. Determine average moisture, yield, and yield/moisture Ears from the twenty best parents, based on average performance, are saved for replanting
Ear 2 Ear 4 Ear 1 Ear 3 Ear 6 Ear 8 Ear 5 Ear 7 MERS -Ear 3 was one of the 20 best parent ears of the 200 being tested -We will save the best 10 ears from this row -In this way we will get 200 OP ears from the best 20 parent ears for next year s selection
Why is MERS better? Looking at the offspring better evaluates each parent plant Randomization across three environments helps to reduce G x E effects A good experimental layout will help to reduce E effects on yields and other traits All seed has been outcrossed with bulk pollen to reduce inbreeding and evaluate General Combining Ability Much faster yield improvement is possible if the extra work can be carried out! Team approach? I have a new spreadsheet tool for anyone who wants to try MERS. It is preloaded with a field randomization and calculations of averages for all measured traits relative to controls throughout each field.
What else would intensify selection? Leave plants standing late into the season Weigh and reweigh the ears Germination tests for each ear Nutrient tests for each ear Check variety(ies) throughout the field to better evaluate environmental variation Use checks as a standard
Target Environment!
Pollen Control: Sibs, Selfs Ear to Row Selection
What about contamination by transgenes? Seed stock can become contaminated Seed mixing can introduce transgenes Transgenes can contaminate crop via pollination
There are 3 known strong alleles: Ga1 s Ga2 s Tcb1 s David Podoll with his Dakota Black Popcorn
Pollen tubes growth range in silks of maize inbred line K55 harbouring different allele combinations of Ga1s. 2010 The Author(s). Lausser A et al. J. Exp. Bot. 2009;61:673-682
Working with Gametophytic Incompatibility Genes: Cross Seed Set Genotypes of Progeny Ga1 s Ga1 s x gaga None gaga x Ga1 s Ga1 s Normal Ga1 s ga Ga1 s ga x gaga Normal Ga1 s ga, gaga Ga1 s Ga1 s x Ga1 s ga Normal Ga1 s Ga1 s Ga1 s ga x Ga1 s ga Normal Ga1 s ga, Ga1 s Ga1 s Adapted from Thomas, W.I. 1955. Agron. J. 47:440-441.
Dziękuję! Thank You! Merci! Frank Kuka fkutka@npsas.org 701-25-7853 Cornculture.info and on Facebook